[
https://issues.apache.org/jira/browse/KAFKA-14196?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17601609#comment-17601609
]
Luke Chen commented on KAFKA-14196:
-----------------------------------
# Should we consider the difference between cooperative and eager protocol.
Because, cooperative doesn't revoke all partitions. However, I worry that the
subscription might change during the onJoinPrepare, so I meant there could be
edge cases we need to handle here.
--> I think we should consider the difference between cooperative and eager
protocol, because one of the purpose for cooperative rebalance is to allow
"non-revoking" partitions can keep processing during rebalance. About the edge
case, I think that's fine because in the your PR, we'll check and pause the
partitions each time we enter onJoinPrepare, right? So, even if there's
subscription change while we're waiting commitAsync, we can pause the updated
subscription partitions in onJoinPrepare each time. WDYT?
# I believe this only applies to autocommit enabled. I think for
non-autocommit case, user should handle the offset during the revocation, so we
are good there?
--> Yes, we only need to worry about autocmmit enabled case
> Duplicated consumption during rebalance, causing OffsetValidationTest to act
> flaky
> ----------------------------------------------------------------------------------
>
> Key: KAFKA-14196
> URL: https://issues.apache.org/jira/browse/KAFKA-14196
> Project: Kafka
> Issue Type: Bug
> Components: clients, consumer
> Affects Versions: 3.3.0, 3.2.1
> Reporter: Philip Nee
> Assignee: Philip Nee
> Priority: Major
> Labels: new-consumer-threading-should-fix
>
> Several flaky tests under OffsetValidationTest are indicating potential
> consumer duplication issue, when autocommit is enabled. I believe this is
> affecting *3.2* and onward. Below shows the failure message:
>
> {code:java}
> Total consumed records 3366 did not match consumed position 3331 {code}
>
> After investigating the log, I discovered that the data consumed between the
> start of a rebalance event and the async commit was lost for those failing
> tests. In the example below, the rebalance event kicks in at around
> 1662054846995 (first record), and the async commit of the offset 3739 is
> completed at around 1662054847015 (right before partitions_revoked).
>
> {code:java}
> {"timestamp":1662054846995,"name":"records_consumed","count":3,"partitions":[{"topic":"test_topic","partition":0,"count":3,"minOffset":3739,"maxOffset":3741}]}
> {"timestamp":1662054846998,"name":"records_consumed","count":2,"partitions":[{"topic":"test_topic","partition":0,"count":2,"minOffset":3742,"maxOffset":3743}]}
> {"timestamp":1662054847008,"name":"records_consumed","count":2,"partitions":[{"topic":"test_topic","partition":0,"count":2,"minOffset":3744,"maxOffset":3745}]}
> {"timestamp":1662054847016,"name":"partitions_revoked","partitions":[{"topic":"test_topic","partition":0}]}
> {"timestamp":1662054847031,"name":"partitions_assigned","partitions":[{"topic":"test_topic","partition":0}]}
> {"timestamp":1662054847038,"name":"records_consumed","count":23,"partitions":[{"topic":"test_topic","partition":0,"count":23,"minOffset":3739,"maxOffset":3761}]}
> {code}
> A few things to note here:
> # Manually calling commitSync in the onPartitionsRevoke cb seems to
> alleviate the issue
> # Setting includeMetadataInTimeout to false also seems to alleviate the
> issue.
> The above tries seems to suggest that contract between poll() and
> asyncCommit() is broken. AFAIK, we implicitly uses poll() to ack the
> previously fetched data, and the consumer would (try to) commit these offsets
> in the current poll() loop. However, it seems like as the poll continues to
> loop, the "acked" data isn't being committed.
>
> I believe this could be introduced in KAFKA-14024, which originated from
> KAFKA-13310.
> More specifically, (see the comments below), the ConsumerCoordinator will
> alway return before async commit, due to the previous incomplete commit.
> However, this is a bit contradictory here because:
> # I think we want to commit asynchronously while the poll continues, and if
> we do that, we are back to KAFKA-14024, that the consumer will get rebalance
> timeout and get kicked out of the group.
> # But we also need to commit all the "acked" offsets before revoking the
> partition, and this has to be blocked.
> *Steps to Reproduce the Issue:*
> # Check out AK 3.2
> # Run this several times: (Recommend to only run runs with autocommit
> enabled in consumer_test.py to save time)
> {code:java}
> _DUCKTAPE_OPTIONS="--debug"
> TC_PATHS="tests/kafkatest/tests/client/consumer_test.py::OffsetValidationTest.test_consumer_failure"
> bash tests/docker/run_tests.sh {code}
>
> *Steps to Diagnose the Issue:*
> # Open the test results in *results/*
> # Go to the consumer log. It might look like this
>
> {code:java}
> results/2022-09-03--005/OffsetValidationTest/test_consumer_failure/clean_shutdown=True.enable_autocommit=True.metadata_quorum=ZK/2/VerifiableConsumer-0-xxxxxxxxxx/dockerYY
> {code}
> 3. Find the docker instance that has partition getting revoked and rejoined.
> Observed the offset before and after.
> *Propose Fixes:*
> TBD
--
This message was sent by Atlassian Jira
(v8.20.10#820010)
